1,720,976 research outputs found
Specific primer sets used to amplify by PCR the hepatitis B virus overlapping S/Pol region select different viral variants
Get PDFPCR detection of viral genomes has provided new insights into viral diagnosis. Nowadays, it is the most frequently used nucleic acid testing (qualitative and quantitative) technique. The aim of this study was to analyse the major circulating hepatitis B virus (HBV) variants PCR-amplified by three sets of primers in a patient infected with genotype E. The HBV S/Pol overlapping genomic region was amplified from the serum of an infected child using three primer sets previously described. Sequence analysis corresponding to the HBV S/Pol region revealed the presence of different viral populations depending on the set of primers used. D144A S-escape mutant was detected with two of the primer sets, while the rtL217R mutant within the Pol - conferring resistance to Adefovir - could be picked up with a different pair of primer sets. This study undoubtedly implies that the description of viral polymorphisms should be stated together with the sequence of the primers used for PCR amplification when studies of escape and/or antiviral-resistant HBV mutants are carried out.Fil: Cuestas, María Luján. Universidad de Buenos Aires. Facultad de Medicina. Departamento de Microbiología. Area Virologia; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Mathet, Veronica Lidia. Universidad de Buenos Aires. Facultad de Medicina. Departamento de Microbiología. Area Virologia; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Oubiña, Jose Raul. Universidad de Buenos Aires. Facultad de Medicina. Departamento de Microbiología. Area Virologia; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin
Hepatocellular carcinoma and multidrug resistance: Past, present and new challenges for therapy improvement
Get PDFHepatocellular carcinoma (HCC) is the most common malignancy of the liver and the third cause of cancer death worldwide. Chronic hepatitis due to HBV and HCV infection are two major risk factors for HCC worldwide. Advances in early detection and treatment have improved life expectancy of patients with HCC. However, this disorder remains as a disease with poor prognosis. In fact, epidemiological studies have shown that the median survival of patients is 8 months and approximately 20% of them survive one year, while only 5% remain alive after three years. Additionally, HCC is particularly difficult to treat because of its high recurrence rate, and its resistance to conventional chemotherapy due to, among other mechanisms, the over-expression of several members of the ATP-Binding Cassette (ABC) protein family involved in drugs transport.
Fortunately, there is evidence that these patients may benefit from alternative molecular-targeted therapies.
This manuscript reviews the current knowledges on the etiology, molecular mechanisms involved in HCC development and the current therapy strategies for the management of this malignancy. The challenges in the development of drug delivery systems for the targeting of antitumoral drugs to the liver parenchyma are also discussed. Finally, perspectives in the design of a more efficient pharmacotherapy to overcome multidrug resistance are reviewed.Fil: Cuestas, María Luján. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Investigaciones en Microbiología y Parasitología Médica. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Investigaciones en Microbiología y Parasitología Médica; ArgentinaFil: Oubiña, Jose Raul. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Investigaciones en Microbiología y Parasitología Médica. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Investigaciones en Microbiología y Parasitología Médica; ArgentinaFil: Mathet, Veronica Lidia. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Investigaciones en Microbiología y Parasitología Médica. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Investigaciones en Microbiología y Parasitología Médica; Argentin
Drug delivery systems and liver targeting for the improved pharmacotherapy of the hepatitis B virus (HBV) infection
Get PDFIn spite of the progress made in vaccine and antiviral therapy development, hepatitis B virus (HBV) infection is still the most common cause of liver cirrhosis and hepatocellular carcinoma, with more than 400 million people chronically infected worldwide. Antiviral therapy with nucleos(t)ide analogues and/or immunomodulating peptides is the only option to control and prevent the progression of the disease in chronic hepatitis B (CHB)-infected patients. So far, the current antiviral monotherapy remains unsatisfactory because of the low efficacy and the development of drug resistance mutants. Moreover, viral rebound is frequently observed following therapy cessation, since covalent closed circular DNA (cccDNA) is not removed from hepatocytes by antiviral therapy. First, this review describes the current pharmacotherapy for the management of CHB and the new drug candidates being investigated. Then, the challenges in the development of drug delivery systems for the targeting of antiviral drugs to the liver parenchyma are discussed. Finally, perspectives in the design of a more efficient pharmacotherapy to eradicate the virus from the host are addressed.Fil: Cuestas, María Luján. Universidad de Buenos Aires. Facultad de Medicina. Departamento de Microbiología. Area Virologia; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Mathet, Veronica Lidia. Universidad de Buenos Aires. Facultad de Medicina. Departamento de Microbiología. Area Virologia; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Oubiña, Jose Raul. Universidad de Buenos Aires. Facultad de Medicina. Departamento de Microbiología. Area Virologia; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Sosnik, Alejandro Dario. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Departamento de Tecnología Farmacéutica; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin
Downregulation of mdr1 and abcg2 genes is a mechanism of inhibition of efflux pumps mediated by polymeric amphiphiles
Get PDFThe ability of cells to acquire resistance to multiple pharmaceuticals, namely multidrug resistance (MDR), is often mediated by the over-expression of efflux transporters of the ATP-binding cassette (ABC) superfamily; e.g., P-glycoprotein (P-gp or MDR1), breast cancer resistance protein (BCRP), and multidrug resistance-associated protein MRP1. ABCs pump drug molecules out of cells against a concentration gradient, reducing their intracellular concentration. The ability of polymeric amphiphiles to inhibit ABCs as well as the cellular pathways involved in the inhibition has been extensively investigated. This work investigated for the first time the effect of branched poly(ethylene oxide)-poly(propylene oxide) block copolymers (poloxamines) on the levels of mRNA encoding for MDR1, BCRP and MRP1, in a human hepatoma cell line (Huh7). Copolymers with a broad range of molecular weights and hydrophilic-lipophilic balances were assayed. Results confirmed the downregulation of mdr1 and abcg2 genes. Conversely, the mrp1 gene was not affected. These findings further support the versatility of these temperature- and pH-responsive copolymers to overcome drug resistance in cancer and infectious diseases.Fil: Cuestas, María Luján. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica; ArgentinaFil: Castillo, Amalia Inés. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Investigaciones en Microbiología y Parasitología Médica. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Investigaciones en Microbiología y Parasitología Médica; ArgentinaFil: Sosnik, Alejandro Dario. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica; ArgentinaFil: Mathet, Veronica Lidia. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Investigaciones en Microbiología y Parasitología Médica. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Investigaciones en Microbiología y Parasitología Médica; Argentin
Hepatitis D virus infection in patients with hepatitis B virus occult infection
No full textAguilera et al. have clearly confirmed the usefulness of looking for hepatitis D virus (HDV) in patients showing HBsAg reactivity in serum. However, Ponzetto et al. ,have accurately emphasized the fact that HDV infection may also occur even in the absence of HBsAg detection in serum,as previously showed both in animal models, as well as in humans. Moreover, such results have been recently supported by the dazzling discovery that HDV might be transmitted from infected hepatocytes to descendent cells in spite of the absence of a concomitant HBV infection..Fil: Oubiña, Jose Raul. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Investigaciones en Microbiología y Parasitología Médica. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Investigaciones en Microbiología y Parasitología Médica; ArgentinaFil: Delfino, Cecilia María. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Investigaciones en Microbiología y Parasitología Médica. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Investigaciones en Microbiología y Parasitología Médica; ArgentinaFil: Mathet, Veronica Lidia. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Investigaciones en Microbiología y Parasitología Médica. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Investigaciones en Microbiología y Parasitología Médica; Argentin
Lactosylated poly(ethylene oxide)–poly(propylene oxide) block copolymers for potential active targeting: synthesis and physicochemical and self-aggregation characterization
Get PDFAiming to develop polymeric self-assembly nanocarriers with potential applications in active drug targeting to the liver, linear and branched poly(ethylene oxide)- poly(propylene oxide) (PEO-PPO) amphiphiles were conjugated to lactobionic acid (LA), a disaccharide of galactose and gluconic acid, by the conventional Steglich esterification reaction. The conjugation was confirmed by ATR/FT-IR, 1H-NMR and 13C-NMR spectroscopy. MALDI-TOF mass spectrometry and elemental analysis were employed to elucidate the conjugation extent and the final molecular weight, respectively. The critical micellar concentration (CMC), the size and size distribution and zeta potential of the pristine and modified polymeric micelles under different conditions of pH and temperature were characterized by dynamic light scattering (DLS). Conjugation with LA favored the micellization process, leading to a decrease of the CMC with respect to the pristine counterpart, this phenomenon being independent of the pH and the temperature. At 37ºC, micelles made of pristine copolymers showed a monomodal size distribution between 12.8 and 24.4 nm. Conversely, LA-conjugated micelles showed a bimodal size pattern that comprised a main fraction of relatively small size (11.6-22.2 nm) and a second one with remarkably larger sizes of up to 941.4 nm. The former corresponded to single micelles, while the latter would indicate a secondary aggregation phenomenon. The spherical morphology of LA-micelles was visualized by transmission electron microscopy. Finally, to assess the ability of the LAconjugated micelles to interact with lectin-like receptors, samples were incubated with concanavalin A at 37ºC and the size and size distribution were monitored by DLS. Findings indicated that regardless of the relatively weak affinity of this vegetal lectin for galactose, micelles underwent agglutination probably through the interaction of a secondary site in the lectin with the gluconic acid unit of LA.Fil: Cuestas, María Luján. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Departamento de Tecnología Farmacéutica; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Glisoni, Romina Julieta. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Departamento de Tecnología Farmacéutica; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Mathet, Veronica Lidia. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Investigaciones en Microbiología y Parasitología Médica; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad de Buenos Aires. Facultad de Medicina. Departamento de Microbiología; ArgentinaFil: Sosnik, Alejandro Dario. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Departamento de Tecnología Farmacéutica; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin
Drug-resistant and immune-escape hepatitis B virus mutants, occult hepatitis B infection and coinfections in public hospital patients from Argentina
No full textArgentina exhibits low serological prevalence for Hepatitis B virus (HBV); however, occult hepatitis B infection (OBI) has been reported in blood donors, Amerindians and individuals coinfected with hepatitis C virus (HCV), and/or human immunodeficiency virus (HIV). The aim of this study was to analyze the genetic diversity of HBV and to evaluate serological marker associations and coinfections with HCV and HIV in patients attending and treated in a public hospital in the province of Buenos Aires, Argentina. A total of 189 HBV reactive samples (HBsAg and/or anti-HBc) were analyzed for HBV DNA characterization. All reactive samples were tested for anti-HCV and HIV-antigen/antibody using CMIA assays. Thirty-six samples exhibited detectable HBV DNA, 7 of which were OBI. HBV sequences were classified as subgenotypes A1, A2, B2, D3, F1b, F3 and F4. Mutations related to the ability to escape the host’s immune response, resistance to antiviral therapy and progression to disease were found in patients, partly due to the variable sensitivity of HBsAg, the reverse transcriptase, the basal core promoter and the preCore. HCV and HIV prevalence was 10% and most of the genotypes found in the sequences were genotype 1 and B/F recombinant subtype, respectively. Of the total samples analyzed, 7 exhibited coinfections. This study shows the frequency of OBI, subgenotype distribution, HBV mutations and coinfections, which may have important clinical implications in public hospital patients. Planned prevention, detection and treatment adherence are needed to reduce transmission and morbidity in vulnerable populations.Fil: Delfino, Cecilia María. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Investigaciones Biomédicas en Retrovirus y Sida. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Investigaciones Biomédicas en Retrovirus y Sida; ArgentinaFil: Giorgio, Marianela. Hospital de Agudos Doctor Pedro Fiorito ; Gobierno de la Provincia de Buenos Aires;Fil: García, Gabriela. Hospital de Agudos Doctor Pedro Fiorito ; Gobierno de la Provincia de Buenos Aires;Fil: Sanchez Puch, Silvia. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Investigaciones en Microbiología y Parasitología Médica. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Investigaciones en Microbiología y Parasitología Médica; ArgentinaFil: Outon, Estela. Hospital de Agudos Doctor Pedro Fiorito ; Gobierno de la Provincia de Buenos Aires;Fil: Mathet, Veronica Lidia. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Investigaciones en Microbiología y Parasitología Médica. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Investigaciones en Microbiología y Parasitología Médica; Argentin
Effect of several PEO-PPO amphiphiles on bax, bcl-2, and hTERT mRNAs: An insight into apoptosis and cell immortalization induced in hepatoma cells by these polymeric excipients
Get PDFRecent data have shown that synthetic polymers and nanomaterials display phenotypic effects in cells and signal transduction mechanisms involved in inflammation, differentiation, proliferation, and apoptosis. Aim: This article aims to investigate the effect of poly(ethylene oxide)-poly(propylene oxide) (PEO-PPO) block copolymers with a wide range of biomedical and pharmaceutical applications on apoptosis and/or cell immortalization, by flow cytometry and multiplex RT-PCR for bax, bcl-2, and human telomerase reverse transcriptase (hTERT). Results: PEO-PPO amphiphiles upregulated bax and hTERT and induced apoptosis of two human hepatoma cell lines. Conclusions: PEO-PPO block copolymers - considered safe for human use - can drastically alter gene expression profiles of genes related to apoptosis/cell proliferation.Fil: Castronuovo, Cynthia Celeste. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Investigaciones en Microbiología y Parasitología Médica. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Investigaciones en Microbiología y Parasitología Médica; ArgentinaFil: Cuestas, María Luján. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Investigaciones en Microbiología y Parasitología Médica. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Investigaciones en Microbiología y Parasitología Médica; ArgentinaFil: Oubiña, Jose Raul. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Investigaciones en Microbiología y Parasitología Médica. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Investigaciones en Microbiología y Parasitología Médica; ArgentinaFil: Mathet, Veronica Lidia. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Investigaciones en Microbiología y Parasitología Médica. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Investigaciones en Microbiología y Parasitología Médica; Argentin
GB virus C quasispecies detected in plasma and lymphocyte subsets in a natural human infection
Get PDFGenomic heterogeneity and quasispecies composition of GB virus C (GBV-C) within plasma and lymphocyte subsets in a naturally infected blood donor were investigated. For this purpose, fragments from the 5′ untranslated region (5′ UTR) and the E2 gene recovered from plasma, B and T lymphocytes, were cloned and sequenced. A total of 63 clones was analysed: 95.2% of them (n=60) - obtained from plasma and cells - were assigned to genotype 2b, while only three derived from plasma corresponded to genotyope 3. The G215A transition within this region was present in 90.9% of the clones from B lymphocytes, but absent in the remaining cell compartments (P<0.01). Apparently, most of the circulating GBV-C quasispecies in this blood donor were related to the viral population infecting CD8+ T cells, and B cells to a lesser extent. This is the first report showing the quasispecies nature of GBV-C in lymphocyte subsets within peripheral blood mononuclear cells. © 2010 SGM.Fil: Ruiz, Vanesa. Universidad de Buenos Aires. Facultad de Medicina; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Giordano, Mirta Nilda. Academia Nacional de Medicina de Buenos Aires; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Rivero, Cintia Wanda. Universidad de Buenos Aires. Facultad de Medicina; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Minassian, Maria Laura. Universidad de Buenos Aires. Facultad de Medicina; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Cuestas, María Luján. Universidad de Buenos Aires. Facultad de Medicina; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Trinks, Julieta. Universidad de Buenos Aires. Facultad de Medicina; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Mathet, Veronica Lidia. Universidad de Buenos Aires. Facultad de Medicina; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Oubiña, Jose Raul. Universidad de Buenos Aires. Facultad de Medicina; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin
Antiviral activity against the hepatitis C virus (HCV) of 1-indanone thiosemicarbazones and their inclusion complexes with hydroxypropyl-β- cyclodextrin
Get PDFThe hepatitis C virus (HCV) is a major cause of acute and chronic hepatitis in humans. Approximately 5% of the infected people die from cirrhosis or hepatocellular carcinoma. The current standard therapy comprises a combination of pegylated-interferon alpha and ribavirin. Due to the relatively low effectiveness, the prohibitive costs and the extensive side effects of the treatment, an intense research for new direct-acting anti-HCV agents is taking place. Furthermore, NS3 protease inhibitors recently introduced into the market are not effective against all HCV subgenotypes. Thiosemicarbazones (TSCs) have shown antiviral activity against a wide range of DNA and RNA viruses. However, their extremely low aqueous solubility and high self-aggregation tendency often preclude their reliable biological evaluation in vitro. In this work, we investigated and compared for the first time the anti-HCV activity of two 1-indanone TSCs, namely 5,6-dimethoxy-1-indanone TSC and 5,6-dimethoxy-1- indanone N4-allyl TSC, and their inclusion complexes with hydroxypropyl-β- cyclodextrin (HPβ-CD) in Huh-7.5 cells containing the full-length and the subgenomic subgenotype 1b HCV replicon system. Studies of physical stability in culture medium showed that free TSCs precipitated rapidly and formed submicron aggregates. Conversely, TSC complexation with HPβ-CD led to more stable systems with minimal size growth and drug concentration loss. More importantly, both TSCs and their inclusion complexes displayed a potent suppression of the HCV replication in both cell lines with no cytotoxic effects. The mechanism likely involves the inhibition of non-structural proteins of the virus. In addition, findings suggested that the cyclodextrin released the drug to the culture medium over time. This platform could be exploited for the study of the drug toxicity and pharmacokinetics animal models.Fil: Glisoni, Romina Julieta. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Departamento de Tecnología Farmacéutica; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Cuestas, María Luján. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Departamento de Tecnología Farmacéutica; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Mathet, Veronica Lidia. Universidad de Buenos Aires. Facultad de Medicina. Departamento de Microbiología. Área Virología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Oubiña, Jose Raul. Universidad de Buenos Aires. Facultad de Medicina. Departamento de Microbiología. Área Virología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Moglioni, Albertina Gladys. Universidad de Buenos Aires; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Sosnik, Alejandro Dario. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Departamento de Tecnología Farmacéutica; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin
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